Plunger pump or motor

ABSTRACT

A plunger pump or motor provided with a solid particle removing mechanism characterized in that the ports of the cylinder block are radially larger than the ports of the port plate, that two radially elongated openings are formed in the contacting surface of the cylinder block and traverse annular areas of the port plate, which are partly in common with an annular area to be traversed by the ports of the cylinder block, and that the openings do not communicate with the ports. The particles removed by the openings may be expelled out of the cylinder block by the centrifugal force.

United States Patent [72] Inventor KenjiNinomiya Kawasaki-shi, Japan 887,234

Dec. 22, 1969 Jan. 11, 1972 Kabushiki Kaisha Komatsu Seisakusha [21 Appl. No. [22] Filed [45] Patented [73] Assignee (Komatsu, Ltd.) Akasaka, Tokyo, Japan [32] Priority Dec. 25, 1968 [33] Japan [31 43/94502 [54] PLUNGER PUMP OR MOTOR 6 Claims, 6 Drawing Figs.

[52] U.S.Cl 91/487, 137/625 .21 [51] 1nt.Cl .1 F0lb1/00, FOlb 3/00, FOlb 13/04 [50] Field of Search 91/484,

[56] References Cited UNITED STATES PATENTS 2,155,455 4/1939 Thoma 91/489 2,331,694 10/1943 Jeffrey 91/486 3,131,605 5/1964 La Borde 91/485 3,170,297 2/1965 Larson 91/485 3,249,061 5/1966 Ricketts 91/486 Primary Examiner-Carlton R. Croyle Assistant Examiner-John J. Vrablik Att0rney-Steinberg & Blake ABSTRACT: A plunger pump or motor provided with a solid particle removing mechanism characterized in that the ports of the cylinder block are radially larger than the ports of the port plate, that two radially elongated openings are formed in the contacting surface of the cylinder block and traverse annular areas of the port plate, which are partly in common with an annular area to be traversed by the ports of the cylinder block, and that the openings do not communicate with the ports. The particles removed by the openings may be expelled out of the cylinder block by the centrifugal force.

PLUNGER PUMP OR MOTOR This invention relates in general to fluid pressure translating device of the reciprocating type, and more particularly to solid particles removing mechanism for removing solid particles from a clearance between a fixed member such as the port plate and a rotating member such as the cylinder block of a plunger pump or motor.

It is well known that a plunger pump or motor is provided with a port plate and a cylinder block. A plurality of cylinders are formed in the cylinder block, in each of which a plunger is adapted to be reciprocated, being guided by a swashplate, while the cylinder block is rotated on an axis. A liquid medium is sucked into the cylinders and exhausted out thereof. In both the sucking and the exhausting operations, the liquid medium is passed through ports formed in the cylinder block communicating with the cylinders, respectively, and ports formed in the port plate communicating with the external conduits, respectively, for distributing the liquid medium.

A plane surface of the cylinder block provided with the ports is adapted to be rotated on a plane surface of the port plate provided with the ports, being kept in contact therewith under pressure, so as to constitute a pressure seal, and therefore, if these surfaces have been worn, the efficiency of the pump or motor suddenly lowers and the reliability thereof is lost.

In general, the highly pressured sealing surfaces are continuous along a circle, and therefore, when a solid particle is once inserted between these surfaces, it is very hard to remove the solid particle. If the rotation of the cylinder block is continued as it is, the pressure is suddenly lowered and the efficiency of the pump or motor is immediately made inferior.

In the plunger pump or motor of the class described, the abrasion due to solid particles in the liquid medium is large and significant. It has been proved that the efficiency of such a pump or motor is lowered in such a manner as above down to such an extend that it is impossible to overlook the fact, even if durability continues for a short period.

It has been well known to provide a solid particle removing mechanism comprising a pair of radially elongated openings 11 and 11' as shown in FIG. 4. However, the inner end of the radially outer opening 11 is not extended internally to the external extremities 12 of the ports of the cylinder block and the outer end of the radially inner opening 1 I is not extended externally to the internal extremities 13 of the ports, on the ground that, if they are further extended, the openings 11 and II would communicate with the ports formed in the cylinder block and the port plate, to lower the pressure of the liquid medium passing the ports. Under these circumstances, there are remained two annular regions 14 and 15, which are traversed by neither of the ports nor the openings. If a solid particle is received between such annular regions 14 and 15, it is never removed.

The principal object of this invention is to provide a plunger pump or motor of the class described, which is provided with an improved solid particle removing mechanism.

Another object of this invention is to provide a plunger pump or motor of the class described, which is provided with an automatic solid particle removing mechanism.

Still another object of this invention is to provide a plunger pump or motor of the class described, which may be satisfactorily operated for a very considerable length of time without requiring any repairs or attention in connection with solid ingredient in the liquid medium, by virtue of the solid parti :le removing mechanism.

Briefly stated in accordance with one aspect of this invention, there is provided a plunger pump or motor comprising a fixed member, for example, a port plate, and a rotatable member, for example, a cylinder block, which is rotatable relative to and in contact with the fixed member, and has a rotating axis normal to a plane surface thereof adapted to slide on another plane surface of the fixed member. The firstnamed plane surface has a plurality of ports and the secondnamed plane surface also has a plurality of ports, both ports being arranged along a single circle having the center in the axis. The radial dimension of the first-named port differs from the radial dimension of the second-named port. A pair of radially elongated openings are formed in the first-named plane surface and arranged in such a manner that any portion of the second-named plane surface traverses any of the first-named ports or either of the two openings within a single rotation of the rotatable member but the formers not simultaneously with the latters, and either of the openings is not in direct communication with any of the first-named and the secondnamed ports.

In other words, one of the radial ends of the pair of radially elongated openings opposite with each other is positioned between a circle, on which ones of the radial extremities of the first-named ports are arranged, respectively, and another circle, on which ones of the radial extremities of the secondnamed ports are arranged, respectively, and the other of the radial ends of the pair is positioned between still another circle, on which the others of the radial extremities of the firstnamed ports are arranged, respectively, and further another circle, on which the others of the radial extremities of the second-named ports are arranged, respectively.

The invention will be better understood and other objects and additional advantages of the invention will become apparent upon perusal of the following description taken in connection with the drawings, in which:

FIG. 1 is an end view of a cylinder block of a plunger pump embodying this invention;

FIG. 2 is an end view of a port plate for cooperation therewith;

FIG. 3 is an explanatory view showing the relation of the cylinder block with the port plate shown in FIGS. 1 and 2;

FIG. 4 is an explanatory view corresponding to FIG. 3 but in accordance with the prior art;

FIG. Sis an enlarged view of the part P in FIG. I; and

FIG. 6 is a cross-sectional view taken along the line 6-6 of FIG. 5.

Similar numerals refer to similar parts throughout the several views.

Referring more particularly to the drawings, the preferred embodiment of this invention will now be described; however, this description will be understood to be illustrative of the invention and not as limiting it to the particular construction as shown and described. There is a rotatable member such as a cylinder block 16. There are a plurality of ports I7 formed in an end plane surface of the cylinder block 16 and arranged along a pitch circle 26 (FIG. 5) having the center in the axis of rotation of the cylinder block 16.

There is a fixed member such as a port plate 19. There are a plurality of ports 20 formed in an end plane surface of the port plate 19 and arranged along the same pitch circle 26 so that the ports 20 are matched with the ports 17 for flow of a pressured liquid medium.

In this embodiment, the ports 17 are radially larger than the ports 20. The external extremities 37 of the ports 17 are positioned radially beyond the external extremities 39 of the ports 20, and the internal extremities 38 of the ports 17 are positioned radially inwardly beyond the internal extremities 40 of the ports 20, as shown in FIGS. 3 and 5, so that there are an annular plane surface between the circle 37 and 39 and another annular plane surface between the circles 38 and 40. The ports 17 radially overlap these two annular plane surfaces when the cylinder block 16 is rotated ports 20 are situated therebetween.

There are a pair of radially elongated openings 23 and 24 formed in the end plane surface of the cylinder block 16. The openings 23 and 24 are arrangedbetween two radii of the end plane surface, which are apart from any of the ports 17. The inner end 32 of the outer opening 24 is extended internally to an intermediate point between the circles 37 and 39. The outer end 31 of the inner opening 23 is extended externally to an intermediate point between the circles 38 and 40. By virtue of this arrangementof the openings 23 and 24, these openings circumferentially traverse the two annular plane surfaces radially outside a circle 41 arranged between the circles 37 and 39 and radially inside a circle 42 arranged between the circles 38 and 40, so that the two annular surfaces 25 between the circles 37 and 41 and between the circles 42 and 38 are overlapped not only by the ports 17 but also by either of the openings 23 or 24. Of course, the annular surface between the circles 39 and 40 is traversed by the ports 20.

Thus any point in the plane surfaces of contact between the cylinder block 16 and the port plate 19 is traversed as shown in FIG. 6, by one of the ports 17, and the openings 23 and 24, so that any solid particle inserted in any point in the interface between the plane surfaces is removed by being traversed by the ports or the openings and taken up thereinto, within a single rotation of the cylinder block 16.

In this embodiment, the radially outer opening 24 is externally extended to the periphery of the cylinder block 16 as a groove and opened in the peripheral side thereof. The radially inner opening 23 is communicated with the external space of the cylinder block 16 by means of an internal conduit 33 formed inside the cylinder block 16 and extended from the radially outer end 31 to the peripheral side of the cylinder block 16, as shown in FIG. 6. By virtue of the radial direction of theopenings 23 and 24 and the closed conduit 33, any solid particle taken up into the openings 23 and 24 is expelled into the external space of the cylinder block 16 by the action of the centrifugal force produced by rotating the cylinder block 16.

Numerals 27, 28, 29 and 30 denote the radii of the circles 37, 39, 40 and 38, respectively.

It is apparent that with the above-described structure the port plate 19 and cylinder block 16 have the end faces illustrated in FIGS. 1 and 2 engaging each other along an annular area of contact defined between the outer peripheral circle indicated in FIG. 6 at the outer peripheries of the block 16 and port plate 19 and the inner peripheral circle situated at the port plate 19 at the edge thereof shown in FIG. 6 just above the inner end of the elongated radial opening 23. The ports 17 formed in the end face of the cylinder block have inner and outer extremities respectively situated along the concentric intermediate inner circles 38 and 37 indicated in FIG. 5, these circles being concentric with the peripheral circles and situated between the peripheral circles, radially spaced therefrom. The elongated opening 24 is formed in the end face of the cylinder block and extends from the outer peripheral circle across the outer intermediate circle 37 and terminates at an inner end 32 situated between the intermediate circles 37 and 38. The inner elongated radial opening 23 extends from the inner peripheral circle across the inner intermediate circle 38 and terminates in an outer end situated between the circles 37 and 38 closer to the axis of the cylinder block than the inner end 32 of the elongated opening 24. Thus, the entire area of contact between the cylinder block 16 and port plate 19 will be swept through either by the opening 17 or by the radial elongated openings 23 and 24. These openings are located along a common radius, as is apparent from FIG. 5, and as is apparent from FIG. 1 they are the only openings formed in the end face of the cylinder block 16 in addition to the cylinder ports 17. Also, it is clear that the ports 20 of the port plate 19 have inner and outer extremities extending along concentric circles 40 and 39, respectively, shown in FIG. 5, which are spaced from and situated radially between the inner end 32 of the elongated opening 24 and the outer end of the elongated opening 23, so that the valving action between the ports Mind the port 17 is not influenced in any way by the elongated radial openings 23 and 24. The outer open end of the elongated opening 24 permits particles received therein to be centrifugally discharged during rotation of the cylinder block while the bore 33 forms a means for discharging centrifugally particles received in the opening 23, during rotation of the cylinder block.

While a particular embodiment of this invention has been illustrated and described, modifications thereof will readily occur to those skilled in the art. It should be understood there fore that the invention is not limited to the particular arran ement disclosed but that the appended claims are rntende to cover all modifications which do not depart from the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a plunger pump or motor, a rotary cylinder block and a port plate respectively having end faces engaging each other and having an annular area of contact defined between inner and outer peripheral circles concentrically surrounding the axis of said cylinder block, so that during rotation of the latter about said axis with respect to said port plate said end faces slidably engage each other at said annular area of contact, said cylinder block being formed at said end face thereof with ports circumferentially distributed about said axis and all having inner and outer radial extremities extending along inner and outer intermediate circles which are concentric with and spaced radially between said inner and outer peripheral circles, and said end face of said cylinder block being formed between and spaced from a pair of said ports thereof with a pair of elongated radially extending inner and outer openings, said elongated outer opening extending radially from said outer peripheral circle across said outer intermediate circle and having an inner end situated between said intermediate circles while said inner elongated opening extends from said inner peripheral circle across said inner intermediate circle and has an outer end situated between said intermediate circles at a radial distance from said axis of said block which is less than the radial distance of said inner end of said outer elongated opening from said axis, so that during rotation of said block with respect to said port plate the entire area of contact therebetween is swept by said ports of said cylinder block and said elongated radial openings formed in said end face thereof, said elongated outer opening having an open outer end through which particles received in said outer opening will be centrifugally discharged during rotation of said block, and means communicating with said inner elongated opening for centrifugally discharging particles received therein during rotation of said block.

2. The combination of claim 1 and wherein said elongated openings are located along a common radius.

3. The combination of claim I and wherein said inner and outer elongated openings in said end face of said cylinder block are the only openings formed in said end face beside said ports of said cylinder block.

4. The combination of claim 1 and wherein said means for centrifugally discharging particles from said inner elongated opening includes a portion of said cylinder block formed with a bore extending from the exterior of said block substantially radially up to and communicating with said inner elongated opening.

5. The combination of claim I and wherein said port plate is formed with ports communicating with said ports of said cylinder block, and said ports of said port plate being situated at said .end face thereof along a circle concentric with the other circles, said ports of said port plate respectively having inner and outer radial extremities extending along a pair of circles concentric with the other circles and spaced radially from and situated between the outer end of said inner elongated opening and the inner end of said outer elongated open ing, while extending across the ports of said end face of said cylinder block between the inner and outer extremities thereof, so that the valving action between said ports of said port plate and said ports of said cylinder block is in no way influenced by said elongated openings in said end face of said cylinder block.

6. The combination of claim 5 and wherein said elongated openings in said end face of said cylinder block are formed along a common radius and form the only openings in said end face of said cylinder block in addition to said ports thereof. 

1. In a plunger pump or motor, a rotary cylinder block and a port plate respectively having end faces engaging each other and having an annular area of contact defined between inner and outer peripheral circles concentrically surrounding the axis of said cylinder block, so that during rotation of the latter about said axis with respect to said port plate said end faces slidably engage each other at said annular area of contact, said cylinder block being formed at said end face thereof with ports circumferentially distributed about said axis and all having inner and outer radial extremities extending along inner and outer intermediate circles which are concentric with and spaced radially between said inner and outer peripheral circles, and said end face of said cylinder block being formed between and spaced from a pair of said ports thereof with a pair of elongated radially extending inner and outer openings, said elongated outer opening extending radially from said outer peripheral circle across said outer intermediate circle and having an inner end situated between said intermediate circles while said inner elongated opening extends from said inner peripheral circle across said inner intermediate circle and has an outer end situated between said intermediate circles at a radial distance from said axis of said block which is less than the radial distance of said inner end of said outer elongated opening from said axis, so that during rotation of said block with respect to said port plate the entire area of contact therebetween is swept by said ports of said cylinder block and said elongated radial openings formed in said end face thereof, said elongated outer opening having an open outer end through which particles received in said outer opening will be centrifugally discharged during rotation of said block, and means communicating with said inner elongated opening for centrifugally discharging particles received therein during rotation of said block.
 2. The combination of claim 1 and wherein said elongated openings are located along a common radius.
 3. The combination of claim 1 and wherein said inner and outer elongated openings in said end face of said cylinder block are the only openings formed in said end face beside said ports of said cylinder block.
 4. The combination of claim 1 and wherein said means for centrifugally discharging particles from said inner elongated opening includes a portion of said cylinder block formed with a bore extending from the exterior of said block substantially radially up to and communicating with said inner elongated opening.
 5. The combination of claim 1 and wherein said port plate is formed with ports communicating with said ports of said cylinder block, and said ports of said port plate being situated at said end face thereof along a circle concentric with the other circles, said ports of said port plate respectively having inner and outer radial extremities extending along a pair of circles concentric with the other circles and spaced radially from and situated between the outer end of said inner elongated opening and the inner end of said outer elongated opening, while extending across the ports of said end face of said cylinder block between the inner and outer extremities thereof, so that the valving action between said ports of said port plate and said ports of said cylinder block is in no way influenced by said elongated openings in said end face of said cylinder block.
 6. The combination of claim 5 and wherein said elongated openings in said end face of said cylinder block are formed along a common radius and form the only openings in said end face of said cylinder block in addition to said ports thereof. 